柔长结构气固耦合的线性与非线性气动力理论

针对柔性结构与风在三方向相互作用的特点,在合理的结构节段力学模型的基础上,建立了新的气动力模型,即三分力系数C_i=C_i(β(t),θ),(#em/em#=D,L,M)不仅是瞬时攻角的函数,而且也是转速的函数,并依据“片条理论”与改进的“准静态理论”,提出了推导结构节段模型与风相互作用的线性与非线性气动力项的方法,从而将土木工程中柔性结构与风的相互作用的线性与非线性理论集中到一个模型中.对于线性气动力部分,给出了与经典气动力公式中相对应的颤振导数的半解析表达式.对于非线性气动力部分,给出了扭转气动耦合的非线性气动力表达式,并给出了Tacoma大桥扭转非线性运动的控制方程,其形式与结果与V.F.B-m的相吻合.

Linear and Nonlinear Aerodynamic Theory of InteractionBetween Flexible Long Structure and Wind

In light of the characteristics of the interactions between flexible structure and wind in three directions, and based on the rational mechanical section-model of structure, a new aerodynamic force model is accepted, i. e. the coefficients of three component forces are the functions of the instantaneous attack angle and rotational speed C_i=C_i(β(t),θ),(#em/em#=D,L,M). so, a new method to formulate the linear and nonlinear aerodynamic items of wind and structure interacting has been put forward in accordance with "strip theory" and modified "quasi-static theory", and then the linear and nonlinear coupled theory of super-slender structure for civil engineering analyzing are converged in one model. For the linear aerodynamic-force parts, the semi-analytical expressions of the items so called "flutter derivatives" corresponding to the one in the classic equations have been given here, and so have the nonlinear parts. The study of the stability of nonlinear aerodynamic-coupled torsional vibration of the Old Tacoma Bridge shows that the form and results of the nonlinear control equation in rotational direction are in agreement with that of V. F. Bhm's.